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Our dairy road is distorted like old vinyl



Imagine standing in a dense forest. How would you understand the size and shape of this forest from your limited perspective? We do not see the woods for trees is a good analogy to what astronomers experience when trying to estimate the size and shape of our galaxy – we take a small star built into the system inside the Milky Way Drive. We can not fly over the galactic plane to peer into the general shape of our galaxy (though how cool it is?).

Researchers, however, were determined to understand the true form of the Milky Way while they were embedded in it. That's how they did it: A team of National Astronomical Observatories of the Chinese Academy of Sciences (NAOC) and Macquarie University in Australia are studying 1339 bright pulsing stars called Cepheid variables to create a 3-D map of our galaxy.

What they found came as a surprise: We live in a distorted galaxy.

"We usually think spiral galaxies are quite flat, like Andromeda, which you can easily see through a telescope," says astronomer and research associate Richard de Grece at Macquarie University. But our galaxy is not like Andromeda. It has an S-bend that twists away from the galactic center. At this turn, the gravitational attraction of the galaxy becomes weaker, making it look like old vinyl that has become distorted.

The study, which is published in the journal Nature Astronomy, uses data from Wase's extensive infrared researcher (WISE) to accurately determine the location of cephaids in our galactic disk and to turn them into a powerful tool for crossing the dust. , gas and other stars that blur our gaze.

"It is known that it is difficult to determine the distance from the sun to parts of the Milky Way external gas disk without any clear idea of ​​what this disk looks like," said Chen Xiaodian, NAOC researcher and lead author of the study. separate press release. "However, we have recently published a new catalog of well-managed variable stars, known as classic cefeids, for which distances of 3 to 5 percent accuracy can be determined."

Cepheids are young stars that are four to twenty times the mass of our sun and live fast and die young by consuming all their fuel for only a few million years and burning up to 100,000 times brighter than our star. But what they lack in life, they compensate in regular pulses of brightness that can be used by astronomers to accurately measure distances, and in this case they have acted as markers to draw the distorted Milky Way disk.

Though the Milky Way does not fit the standard flat disk exposed to other spiral galaxies (like Andromeda), it is not alone. From earlier observations, researchers identified a dozen other galaxies of similar S-shape that gave them an idea of ​​why our galaxy is distorted.

"By combining our results with these other observations, we came to the conclusion that the twisted spiral pattern of the Milky Way is most likely caused by" torque "- or rotating forcing – from the massive internal disk," adds Liu Chao, co-author of the study. In general, the orbital movements in the massive central area of ​​the Milky Way gravitationally harass the less massive outer regions, which makes them bend and bend in shape.

In the end, this new finding can help us better understand the dynamics of orbital movements within the Milky Way, thus giving insight into the development of our galaxy.


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